The epilepsies are a family of disorders of brain dynamics. Epilepsy patients are susceptible to seizures (changes in sensation, awareness, or behavior caused by brief electrical disturbances in the brain). Often, the electrical disturbances originate from a "focus" or "epileptogenic zone" in part of the brain, from which the disturbances are propagated to other parts of the brain. Epilepsy affects approximately 2.5 million persons in the United States, and over 50 million persons worldwide, and 150,000 to 200,000 new cases occur annually in the U.S. Although most epilepsy patients can control their seizures with the use of antiepileptic drugs, between 20% to 25% of patients cannot bring their seizures under control using drug therapy. Many patients with pharmacologically intractable seizures can eliminate their disability largely or completely by neurosurgical intervention, which typically involves resection of tissue in the epileptogenic zone to prevent the spread of electrical disturbances. Candidates for epilepsy surgery are generally evaluated first with scalp EEG telemetry. In approximately 20% of cases, however, intracranial monitoring with brain surface (ElectroCorticoGraphy, or ECoG) and/or depth electrodes is required to determine the site(s) of seizure onset. We propose to develop software tools that will aid the clinician in the identification of the epileptogenic zone from ECoG data, through the multimodal integration of ECoG/depth electrode data with structural (sMRI) and functional (fMRI, PET, SPECT) imaging data, visualization of ECoG data, both in space and time, and analysis of ECoG data. During Phase I, we will design, implement, and validate software to integrate the visualization of ECoG electrode locations on a subject-specific brain surface representation obtained from MRI data, and visualize ECoG activity patterns in both space and time. A principal design objective is the creation of a software tool that can be used by a trained technician to produce a reliable visualization with less than 1 hour of preparation time.